1. Field of the Invention
The present invention generally relates to an engine air intake device configured to execute variable resonance supercharging with respect to the intake air delivered to an internal combustion engine. More specifically, the present invention relates to an engine air intake device provided with two independent volume chambers (collector sections), each of which corresponds to one of two banks for two cylinder groups, two upstream intake pipe portions that connect to the upstream sides of each of the volume chambers, and at least one communication valve configured to allow communication between the two volume chambers. Moreover, the present invention relates to a seal structure for the engine intake device.
2. Background Information
Japanese Laid Open Patent Publication No. H10-37750A discloses a conventional engine air intake device in which the inside of the collector (surge tank) and an upstream portion thereof are divided into two volume chambers by a partition wall and a separation wall is provided inside each of the two volume chambers so as to form an intake passage inside each of the volume chambers. Each of the two cylinder groups is connected to the separate intake passage. A communication valve is provided in the partition wall and a selector valve is provided in each of the separation walls. By opening and closing the communication valve and the selector valves in different combinations, an output increasing effect resulting from resonance supercharging can be achieved in operating regions ranging from low engine speed regions to high engine speed regions.
Japanese Laid Open Patent Publication No. H06-2625 also discloses the torque Characteristic of an internal combustion engine can be improved by using a variable air intake device that is provided with a pair of intake air intake collectors, a communication passage that joins the two intake air intake collectors together such that intake air can flow therebetween, and a control valve arranged and configured to open and close the communication passage in accordance with the engine operating conditions, thereby enabling both resonance supercharging and inertia supercharging to be utilized effectively.
The conventional variable air intake device described in the above mentioned publication is provided with a pair of intake collectors to which branch pipes communicating with groups of cylinders having non-consecutive firing orders are connected. The intake collectors communicate with each other through a communication passage that is made of an aluminum alloy or other cast material and divided into a plurality of communication passages by a partition wall. A control valve is provided in a central portion of each communication passage. When the internal combustion engine is operating in a region of low rotational speed, the control valves are closed so that the two intake collectors are not allowed to communicate with each other and a resonance supercharging effect is obtained due to pulsation of the intake air. When the internal combustion engine is operating in a region of high rotational speed, the control valves are opened so that the two intake collectors can communicate with each other and an inertia supercharging effect is obtained due to the inertia of the intake air column. Each control valve comprises a valve stem and a rectangular valve element coupled to the valve stem. The valve stems of the control valves are supported in bearing holes formed in a partition wall and a side wall at a central portion of each communication passage and the bearing holes are configured to rotatably support the valve stems of the control valves.
In view of the above, it will be apparent to those skilled in the art from this disclosure that there exists a need for an improved engine air intake device. This invention addresses this need in the art as well as other needs, which will become apparent to those skilled in the art from this disclosure.